I am developing libraries for compatibility across a number of Arduino/compatible boards. I know that Arduino boards can be identified by the test "#if defined (AVR_ATmega328P)" and compatibles as well: #if defined(TM4C123GH6PM). There are a few lists of these IDs on the web but are all outdated. I have searched various cores and library code and do not see where these defines are actually defined.
Nick Gammon's Sketch to detect Atmega chip types identifies the chip type. What I'm looking for the board type to define pin configurations, etc.
Where and in what format are board signatures stored? Is there c++ code that can find the board signature? Does anyone know of a site where these signatures are stored and updated by the Arduino community?